Australia
January 17, 2012
Column by Grant Hollaway
Chairman, Australian Cereal Rust Control Program Consultative Committee
Now is the prime time for grain growers to consider which wheat varieties to retain in their cropping program.
As we move into the new year it is time to consider last year’s crop performance and how each variety stood up to the rust outbreaks that occurred in some regions during 2011.
Growers should reflect on each variety’s performance, the effect of rust and management costs and make an informed decision for season 2012.
A recent poll of Australian wheat growers found that 70 percent make variety selections based on yield potential. However, when considering a variety’s yield potential, many growers do not factor in the potential yield penalty or management costs of a rust outbreak.
Data collected by DPI Victoria has found that the level of rust resistance of wheat varieties has a major influence on potential yield losses in the event of a stripe rust outbreak where no management is undertaken:
- Resistant (R) = 0% yield loss.
- Moderately resistant (MR) = 3%.
- Moderately resistant to moderately susceptible (MR-MS) = 17%.
- Moderately susceptible (MS) = 20%.
- Moderately susceptible to susceptible (MS-S) = 26%.
- Susceptible (S) = 65%
- Very susceptible (VS) = 70%.
As these figures show, not factoring in the potential losses of a rust outbreak – both in yield and increased controls costs – can be significant.
The Australian Cereal Rust Control Program Consultative Committee’s ‘Rust Bust’ campaign is encouraging growers to phase out susceptible and very susceptible varieties from their rotation because of the risks posed to the whole industry.
But if these cultivars are grown, then a management plan is needed, ready in advance in case of a rust outbreak.
Experience in south-eastern Australia during 2011, where there were severe rust outbreaks, showed that rust could be controlled when growers had a plan that involved resistant varieties and/or the use of fungicides.
Growers must also consider controlling the green bridge, fungicide options and communication with neighbours to ensure efficient management. Essentially, grain growers must be more effective managers of the disease to ensure varieties’ individual resistance does not breakdown.
Rust becomes a problem in areas where susceptible varieties are grown. They enable inoculum levels to build up on volunteer plants during summer and autumn and give rust an early opportunity to re-establish in commercial crops. Epidemics are more common following wet summers and in wet growing seasons.
Rust can be effectively managed by growing resistant varieties. The level of resistance required varies between regions and these ratings are available online. Often combining the use of varieties with moderate levels of resistance with the use of fungicides can provide effective management of rust.
If a farmer is growing a variety that does not have adequate resistance for their region then a rust management plan outlining additional control will be needed.
A grower’s individual disease management plan must take into account their property’s level of risk, including summer and seasonal rainfall, location and variety selection. More on developing a rust management plan next week …
ENDS
CAPTION: As grain growers consider their 2012 cropping program, investigating alternatives to rust susceptible and very susceptible varieties should be a priority (click on image above for a high resolution version).
More information on selecting varieties for your region can be found at: www.rustbust.com.au
The Rust Bust is an initiative of the Australian Cereal Rust Control Program Consultative Committee, supported by the Grains Research and Development Corporation.
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